Predictive Value of Magnetic Resonance Imaging in Differentiating Between Leiomyoma and Adenomyosis

OBJECTIVE: We evaluated the role of MRI as a preoperative diagnostic tool for leiomyoma and adenomyosis. METHOD: This is a retrospective chart review at a university-based hospital. The study included 1517 women who underwent hysterectomy or myomectomy over a 5-year period, and 153 women with a preoperative pelvic MRI were included. Comparisons were made between the results of the MRI and postoperative pathology reports. RESULTS: The MRI and pathology report were the same for 136 of 144 women with leiomyoma and 12 of 31 women with adenomyosis. The MRI had 94% sensitivity and 33% specificity for leiomyoma and 38% sensitivity and 91% specificity for adenomyosis. Positive and negative predictive values of MRI for leiomyoma were 95% and 27% with 90% accuracy. Positive and negative predictive values of MRI for adenomyosis were 52% and 85%, respectively, with 80% accuracy. CONCLUSION: MRI has a high sensitivity and a low specificity for diagnosing leiomyoma and a high specificity and a low sensitivity for diagnosing adenomyosis. Due to the high cost and technical variations, we suggest using MRI only as an adjunctive diagnostic tool when ultrasound is not conclusive and differentiation between the 2 pathologies ultimately affects patient management.